Alkanes, the most common products from the fossil fuel, are the main components of power oil and a primary source of energy for modern society. They are also important industrial crude materials and solvents. While serving people, the prevalence of alkanes poses a risk to security, environment, and health. Alkanes are flammable and their vapors are extremely explosive when mixed with oxygen. They are also used to make ammonium nitrate/fuel oil (ANFO), a powerful improvised explosive, which is hard to detect. Improper and malicious use of alkanes and their products have brought numerous disasters in recent years, including the Oklahoma City Bombing in 1995. Additionally, according to the Criteria Documents (No. 77-141B) from NIOSH, alkane vapors could lead to toxicity to human nervous and skin system. Such alkane vapors can also be odorless which introduces additional inadvertent exposure risk. Therefore, a reliable, quick, and portable detection method for alkane vapor is necessary for public safety and industrial control. Because of their high volatility, alkanes produce significant vapor, which creates a potential for nondestructive detection by sensors and analytical instruments. However, current technologies still face great challenges on alkane vapor detection, particularly with trace level sensitivity and real-time monitoring. Traditional spectroscopy methods, such as gas chromatography-mass spectrometry (GC-MS) and ion mobility spectroscopy (IMS), are slow, expensive, and complicated to operate. The chemical inertness of alkanes limits the effectiveness of sensing techniques based on direct chemical reactions or interactions, such as electrochemistry, reaction-based fluorescence, and chemiresistors.